Daytime population projections

I am trying to come up with some reasonable forecasts for daytime population in a municipality. Has anyone done this and found things to do and/or avoid. Any advise is appreciated. (I wasn't sure what forum this should go in, so feel free to move it.)

"Oh, that is all well and good, but, voice or no voice, the people can always be brought to the bidding of the leaders. That is easy. All you have to do is tell them they are being attacked and denounce the pacifists for lack of patriotism and exposing the country to danger. It works the same way in any country."